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JP2017092786

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2017092786
PROBLEM TO BE SOLVED: To provide a speaker diaphragm which realizes a speaker which
operates properly and which has excellent acoustic characteristics by enhancing the adhesion
between a magnesium diaphragm and an edge while satisfying the rustproofness of the
magnesium diaphragm. Do. SOLUTION: The speaker diaphragm is a speaker diaphragm including
a diaphragm portion having a base material containing a magnesium alloy, and an edge portion
formed by connecting a resin material to an outer peripheral end portion of the diaphragm
portion. The diaphragm portion has an oxide film layer formed on the entire surface of the
substrate and an electrodeposition coating layer further formed on the surface of the oxide film
layer except for the outer peripheral edge, and the edge portion is The resin material to be
configured is in close contact with and bonded to the oxide film layer at the outer peripheral end
without interposing the electrodeposition coating layer. [Selected figure] Figure 1
Speaker diaphragm, method of manufacturing the same, and speaker using the same
[0001]
The present invention relates to a speaker diaphragm, a method of manufacturing the same, and
a speaker using the same.
[0002]
In the electrodynamic speaker, an edge is connected to the outer peripheral end of the speaker
diaphragm, and a structure for supporting the speaker diaphragm so as to freely vibrate is widely
used.
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1
In the conventional speaker, in addition to the paper diaphragm formed by papermaking, the
material of the speaker diaphragm is formed of a composite diaphragm in which a thermosetting
resin is impregnated in a substrate such as woven fabric or nonwoven fabric, or a resin material.
Various types such as a resin diaphragm and a metal diaphragm formed of a metal material may
be used.
[0003]
In the metal diaphragm, an alloy containing magnesium which is light in weight and relatively
large in internal loss may be used. The magnesium diaphragm is easily rusted due to its excellent
acoustic characteristics as a metal diaphragm. Therefore, a film is formed on the surface by
anodizing treatment or further electrodeposition coating treatment, and then formed on the
speaker diaphragm. It is necessary (patent documents 1 and 2). Conventionally, an oxide film is
partially formed on the diaphragm substrate surface by masking and anodizing at least one
surface of the diaphragm substrate, and an oxide film forming portion and a non-formation
portion on the diaphragm substrate Patent Document 3 discloses a speaker diaphragm that
forms
[0004]
Further, in the conventional speaker, the thickness of the edge is increased on the diaphragm
joint side of the substantially semicircular section in cross section, and the cross sectional shape
of the substantially semicircular section and the diaphragm joint on the front side of the speaker
is the same. What was made to be able to prevent generation of a so-called mid-range valley on
the sound pressure frequency characteristic and obtain a good sound pressure frequency
characteristic by being made to be continuous in a linear or curved shape (Patent Document 4).
[0005]
Also, conventionally, a vibration for a speaker comprising a magnesium diaphragm mainly
composed of magnesium and a resin edge whose inner peripheral edge is joined to an outer
peripheral rim of the magnesium diaphragm in order to attach the magnesium diaphragm to the
frame It is a plate, and the inner peripheral edge of the edge is a structure having a holding
groove to which the outer peripheral edge of the magnesium diaphragm is closely fitted, and the
magnesium diaphragm cuts the outer periphery to a predetermined size and then cuts the outer
peripheral cut surface On the other hand, there is a speaker diaphragm in which the edge is
integrally formed on the magnesium diaphragm by insert molding in a state where the end
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2
surface treatment for rust prevention is not performed (Patent Document 5).
[0006]
Japanese Patent Publication No. 62-16062 Japanese Patent Laid-Open Publication No. 20065458 Japanese Utility Model Laid-Open Publication No. 3-44996 Japanese Patent Laid-Open
Publication No. 7-7790 Japanese Patent No. 4518243
[0007]
However, since the speaker diaphragm having the base material containing the magnesium alloy
needs to be subjected to the surface treatment for rust prevention as described above, the edge
made of the resin material is integrally formed on the magnesium diaphragm by insert molding.
However, there is a problem that the surface treatment may cause damage to the adhesion
between the magnesium diaphragm and the edge.
When a film is formed on the magnesium diaphragm by anodizing treatment and
electrodeposition coating treatment, the surface layer of the electrodeposition coating is uniform
and chemically stable, and the adhesion is deteriorated.
As a result, even if the edge connected to the diaphragm of the magnesium alloy is integrally
formed by insert molding and the thickness of the edge is properly designed to improve the
acoustic characteristics, the magnesium diaphragm and the edge do not contact with each other
Problems such as the generation of noise may occur.
[0008]
The present invention has been made to solve the above-mentioned problems of the prior art,
and its object is to use a diaphragm portion having a base material containing a magnesium alloy
and a resin material at the outer peripheral end portion of the diaphragm portion. A speaker
diaphragm including an edge portion connected and formed, wherein the adhesion between the
magnesium diaphragm and the edge is enhanced while satisfying the corrosion resistance of the
magnesium diaphragm, and the speaker diaphragm operates properly and acoustically. An object
of the present invention is to provide a speaker diaphragm that realizes a speaker with excellent
characteristics.
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[0009]
A speaker diaphragm according to the present invention is a speaker diaphragm including a
diaphragm portion having a base material containing a magnesium alloy, and an edge portion
formed by connecting a resin material to an outer peripheral end portion of the diaphragm
portion. The diaphragm portion has an oxide film layer formed on the entire surface of the
substrate, and an electrodeposition coating layer further formed on the surface of the oxide film
layer except for the outer peripheral edge, and constitutes an edge portion. The resin material to
be bonded is in intimate contact with and bonded to the oxide film layer at the outer peripheral
end without interposing the electrodeposition coating layer.
[0010]
Preferably, in the speaker diaphragm according to the present invention, the edge portion has an
inner diameter convex portion defined by a first inner diameter dimension and an inner diameter
recess defined by a second inner diameter dimension larger than the first inner diameter
dimension. The oxide film layer on the outer peripheral end of the diaphragm portion is exposed
in the range of the first inner diameter dimension to the inner diameter concave portion and the
second inner diameter dimension corresponding to the inner diameter recess.
[0011]
Preferably, in the speaker diaphragm of the present invention, the resin material constituting the
edge portion is a styrene thermoplastic elastomer, an ethylene thermoplastic elastomer, or an
ester thermoplastic elastomer having a JIS-A hardness of 0 ° to 90 °. The resin material is any
one of olefin-based thermoplastic elastomers, and the resin material penetrates into a large
number of holes formed in the oxide film layer of the substrate and adheres closely.
[0012]
In addition, preferably, in the speaker diaphragm of the present invention, the cross-sectional
thickness of the resin material at the edge portion is the largest at the cut end surface portion of
the diaphragm portion, and further, continuously in the radial direction of the diaphragm portion.
It becomes thinner and becomes thinner continuously as it goes radially outward of the edge
portion, and the cut end surface of the diaphragm portion is covered with the resin material.
[0013]
Further, the method for manufacturing a speaker diaphragm according to the present invention
comprises the steps of forming a diaphragm portion having a magnesium alloy base material,
and connecting and molding an edge portion with a resin material at the outer peripheral end of
the diaphragm portion. And the step of forming the diaphragm portion is a step of forming the
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oxide film layer on the entire surface of the substrate, and further electrodeposition coating on
the surface of the oxide film layer excluding the outer peripheral end by masking the outer
peripheral end. And forming the layer by connecting the edge portion, the resin material
constituting the edge portion is brought into intimate contact with the oxide film layer at the
outer peripheral end portion without intervening the electrodeposition coating layer. Including a
bonding step.
[0014]
Further, in the method of manufacturing a speaker diaphragm according to the present
invention, the step of connecting and forming the edge portions is defined by an inner diameter
convex portion defined by the first inner diameter dimension and a second inner diameter
dimension larger than the first inner diameter dimension. The inner diameter recess to be formed
is formed in an annular shape that repeatedly appears in the circumferential direction, and the
oxide film layer on the outer peripheral end of the diaphragm portion in the range from the first
inner diameter dimension to the second inner diameter dimension corresponding to the inner
diameter recess The mold for holding the diaphragm portion includes an outer peripheral end
holding portion holding an area where the oxide film layer is exposed at the outer peripheral end.
[0015]
Moreover, the speaker of the present invention includes any of the above-mentioned speaker
diaphragms.
[0016]
Hereinafter, the operation of the present invention will be described.
[0017]
The speaker diaphragm of the present invention includes a diaphragm portion having a base
material containing a magnesium alloy, and an edge portion formed by connecting a resin
material to an outer peripheral end portion of the diaphragm portion.
The diaphragm portion has an oxide film layer formed on the entire surface of the substrate and
an electrodeposition coating layer further formed on the surface of the oxide film layer except for
the outer peripheral edge, and thus constitutes an edge portion. The resin material is in close
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contact with and bonded to the oxide film layer at the outer peripheral end without interposing
the electrodeposition coating layer.
In addition, the speaker of the present invention is configured to include the speaker diaphragm.
[0018]
In the speaker diaphragm of the present invention, in the process of forming the diaphragm
portion, an oxide film layer is formed on the entire surface of the base material, and the outer
peripheral edge is masked to further add electricity to the surface of the oxide film layer
excluding the outer peripheral edge. Since the coated layer is formed, the resin material
constituting the edge portion can be brought into intimate contact with and bonded to the oxide
film layer at the outer peripheral end without interposing the electrodeposition coated layer.
Therefore, it is possible to realize a speaker that operates properly and has excellent acoustic
characteristics by enhancing the adhesion between the magnesium diaphragm and the edge
while satisfying the corrosion resistance of the magnesium diaphragm.
[0019]
In the speaker diaphragm of the present invention, the resin material constituting the edge
portion is made of a styrene-based thermoplastic elastomer having a JIS-A hardness of 0 ° to 90
°, an ethylene-based thermoplastic elastomer, an ester-based thermoplastic elastomer, and an
olefin-based thermoplastic resin It can be selected from any of the elastomers.
Since the resin material constituting the edge portion enters the porous holes formed in a large
number in the oxide film layer of the base material containing the magnesium alloy, the adhesion
between the magnesium diaphragm and the edge is enhanced, and the edge portion peels, etc.
Malfunction of the speaker can be reduced to realize a properly operating speaker.
[0020]
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In the edge portion of the speaker diaphragm according to the present invention, the inner
diameter convex portion defined by the first inner diameter dimension and the inner diameter
concave portion defined by the second inner diameter dimension larger than the first inner
diameter dimension are plural in the circumferential direction. It may have an annular shape that
appears repeatedly.
In this case, the oxide film layer on the outer peripheral end of the diaphragm portion is exposed
in the range from the first inner diameter dimension to the inner diameter recess corresponding
to the inner diameter recess and less than the second inner diameter.
This is because, in the step of connecting the edge portion to the diaphragm portion and forming
the mold, the mold for clamping the diaphragm portion has an outer peripheral end clamping
portion for clamping the exposed range of the oxide film layer at the outer peripheral end. By
doing this, it is possible to keep the shape of the outer peripheral end of the diaphragm portion
in a predetermined shape, and to flow the resin material forming the edge uniformly.
Therefore, it is possible to realize a properly operating speaker that exhibits predetermined
frequency characteristics.
[0021]
In the speaker diaphragm, the cross-sectional thickness of the resin material at the edge is the
largest at the cut end face of the diaphragm, and further decreases continuously as it goes
radially inward of the diaphragm, and the edge The thickness may be continuously reduced
toward the radially outer side of the portion, and the cut end surface of the diaphragm portion
may be covered with the resin material.
When the cross-sectional thickness of the resin material at the edge changes continuously, the
mechanical impedance changes rapidly and there is no region where the mechanical impedance
changes, and the reflection of the vibration decreases, resulting in frequency characteristics of
the sound wave emitted from the speaker diaphragm and the edge. Peak dip can be suppressed.
Therefore, the reproduction sound quality of the speaker provided with this speaker diaphragm
can be favorably affected.
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[0022]
The speaker diaphragm of the present invention, the method of manufacturing the same, and the
speaker using the same operate properly by enhancing the adhesion between the magnesium
diaphragm and the edge while satisfying the corrosion resistance of the magnesium diaphragm,
and A speaker with excellent acoustic characteristics can be realized.
[0023]
It is a figure explaining the speaker diaphragm by the preferred embodiment of this invention.
(Example 1) It is a figure which illustrates typically the layer structure of the speaker diaphragm
by the preferable embodiment of this invention.
(Example 1) It is a figure explaining the edge part of the speaker diaphragm by the preferable
embodiment of this invention. (Example 1) It is a graph explaining the sound pressure frequency
characteristic of the speaker by a preferred embodiment of the present invention. (Example 1
and Comparative Example 1) It is a figure explaining the speaker diaphragm by the preferred
embodiment of this invention. (Example 2)
[0024]
Hereinafter, although the speaker diaphragm by the preferable embodiment of this invention, its
manufacturing method, and the speaker using the same are demonstrated, this invention is not
limited to these embodiments.
[0025]
FIG. 1 is a view for explaining a speaker diaphragm 10 according to a preferred embodiment of
the present invention.
Specifically, FIG. 1 (a) is a cross-sectional view of the speaker diaphragm 10, and FIG. 1 (b) is an
enlarged cross-sectional view around the edge portion 12. As shown in FIG. In addition,
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illustration and description are abbreviate | omitted about the one part structure unnecessary for
description, an internal structure, etc. FIG.
[0026]
The speaker diaphragm 10 of the present embodiment includes a diaphragm portion 11 having a
base 20 containing a magnesium alloy, and an edge portion 12 formed by connecting a resin
material to an outer peripheral end portion of the diaphragm portion 11. It is a speaker
diaphragm. The speaker diaphragm 10 is a speaker diaphragm in which the edge portion 12 is
integrally formed on the balance dome type diaphragm portion 11 with a styrene thermoplastic
elastomer by insert molding. The speaker diaphragm 10 is a diaphragm used for a circular 4 cm
diameter electrodynamic speaker, and in FIG. 1A, illustration of the left half symmetrical with
respect to the central axis O is omitted.
[0027]
The diaphragm part 11 integrally forms the dome-shaped dome vibration part 11a and the coneshaped cone vibration part 11b by press-forming the sheet-like base material 20 containing a
magnesium alloy. A voice coil coupling portion to which a bobbin of a substantially cylindrical
(not shown) voice coil is coupled is formed at a downward convex ridge line portion which is a
boundary between the dome vibrating portion 11a and the cone vibrating portion 11b. In FIG.
1A, the upper side shown is the front side of the speaker diaphragm 10, the lower side shown is
the rear side of the speaker diaphragm 10, and when the speaker is assembled, the voice coil and
the magnetic circuit are arranged. Side.
[0028]
In the speaker (not shown) using the speaker diaphragm 10, the edge portion 12 formed on the
outer peripheral end 11c of the cone vibrating portion 11b of the speaker diaphragm 10 has a
coil (not shown) of a voice coil (not shown) It is disposed in the magnetic gap of and supports
vibratably without contacting a magnetic circuit or the like. Therefore, when an audio signal
current is supplied to the voice coil, the speaker can vibrate the speaker diaphragm 10 to
reproduce sound.
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9
[0029]
The edge part 12 is connected and shape | molded by the resin material in the outer peripheral
end part 11c of the cone vibration part 11b. The edge portion 12 has inner peripheral
connecting portions 12a and 12b whose cross-sectional shape is a portion covered along the
outer peripheral end portion 11c of the cone vibrating portion 11b, a roll portion 12c whose
cross section is formed in a roll shape, and a gasket 13 And an outer peripheral connecting
portion 12d connected to the ring portion. The inner peripheral connecting portion 12a is a
portion covering the outer peripheral end 11c from the front side, and the inner peripheral
connecting portion 12b is a portion covering the outer peripheral end 11c from the rear side.
Therefore, the cut end surface 11d which defines the outer diameter of the outer peripheral end
11c of the cone vibration portion 11b is covered by the roll portion 12c. The gasket 13 for
keeping the outer diameter portion of the edge portion 12 in a predetermined shape is connected
to a frame (not shown) or a magnetic circuit.
[0030]
FIG. 2 is a diagram schematically illustrating the layer structure of the speaker diaphragm 10.
Specifically, FIG. 2 (a) shows a cross section of the cone vibration part 11b, and FIG. 2 (b) shows a
cross section in the vicinity of the inner peripheral connection part of the outer peripheral end
11c and the edge 12, The layer structure is described. Moreover, FIG.2 (c) is a microscope picture
of the oxide film layer 21 mentioned later.
[0031]
The base 20 of the diaphragm portion 11 is an alloy containing at least 90% or more of
magnesium (Mg), and is a sheet of metal foil having a thickness of 0.045 mm. Magnesium is
advantageous because it is lightweight, has a relatively large internal loss, and is excellent in
acoustic characteristics as a metal diaphragm. However, on the other hand, the surface and back
surface of the substrate 20 are anodized because the metal is extremely weak in corrosion
resistance and easily rusted as compared to other metals and lacks practicability without surface
treatment. It is necessary to form a film by an electrodeposition coating process.
[0032]
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10
An oxide film layer 21 is formed on the front and back surfaces of the base 20. Specifically, the
oxide film layer 21 is an oxide film layer formed on the entire surface (including the back
surface) of the substrate 20 by anodizing treatment. Therefore, the oxide film layer 21 is formed
on both surfaces of the base material 20 in the cone vibration portion 11b shown in FIG. 2A and
the outer peripheral end 11c shown in FIG. 2B. In the anodizing treatment, the base material 20
of the diaphragm portion 11 which is metal in the electrolytic solution is used as an anode (plus
electrode) to supply electricity, and the surface of the base material 20 is positively oxidized by
magnesium oxide. It is a process of forming. The oxide film layer 21 has a thickness of several
micrometers (micron meter) or more, and as shown in FIG. 2C, a porous porous film having a
large number of pores on the surface is formed. The thickness of the oxide film layer 21 is
preferably in the range of 5 to 10 μm depending on the thickness of the substrate 20.
[0033]
In the cone vibration portion 11 b shown in FIG. 2A, an electrodeposition coating layer 22 is
further formed on the oxide film layer 21. In the electrodeposition coating process, the substrate
20 of the diaphragm portion 11 which is metal in the electrodeposition coating solution is used
as an anode (plus electrode), electricity is supplied, and the oxide film layer 21 of the anodized
substrate 20 is applied. Is a step of positively forming the electrodeposition coating layer 22. The
electrodeposition coating layer 22 has a thickness of several μm (micron meter) or more, and
preferably in the range of 5 to 10 μm according to the thickness of the substrate 20. When the
electrodeposition coating layer 22 is further formed on the oxide film layer 21, the surface layer
of the electrodeposition coating layer 22 is uniform and chemically stable, and therefore,
compared with the case of the oxide film layer 21 alone, There is an advantage that it comes to
be excellent in corrosion resistance.
[0034]
On the other hand, the electrodeposition coating layer 22 is not further formed on the oxide film
layer 21 in the vicinity of the outer peripheral end 11 c of the cone vibrating portion 11 b and
the inner peripheral connecting portion of the edge 12 shown in FIG. In the step of forming the
electrodeposition coating layer 22, the outer peripheral end 11 c of the cone vibration portion 11
b is masked to further form the electrodeposition coated layer 22 on the surface of the oxide film
layer 21 excluding the outer peripheral end 11 c. . The masking is a masking tape of a
nonconductive material so that the electrodeposition coating layer 22 is not formed on the oxide
film layer 21 on the outer peripheral end 11 c corresponding to the outer peripheral end 11 c
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11
forming the edge 12. It may be pre-processed by pasting, etc., or by sandwiching and protecting
with a mold of non-conductive material, applying a paint in advance, etc. Therefore, in the step of
connecting and molding the edge portion 12 with the resin material, the outer peripheral end
portion of the diaphragm portion 11 on which the inner peripheral connecting portions 12a and
12b of the edge 12 are formed if the masking is peeled off or removed. The oxide film layer 21 is
exposed to 11c.
[0035]
Subsequently, in the step of connecting and molding the edge portion 12 with a resin material,
the vibrating portion 11 is placed on a predetermined mold, and the edge portion 12 is integrally
molded on the outer peripheral end portion 11 c of the cone vibrating portion 11 b. As described
above, since the oxide film layer 21 is exposed at the outer peripheral end 11c, the edge portion
12 is in close contact with the oxide film layer 21 at the outer peripheral end 11c without the
electrodeposition coating layer 22 being interposed. can do. Since the oxide film layer 21 is
formed with a porous porous film having a large number of pores on the surface as shown in FIG.
2 (c), a porous state in which a large number of resin materials constituting the edge portion 12
are formed. As a result, the adhesion between the vibrating portion 11 which is a magnesium
diaphragm and the edge 12 can be enhanced. The speaker provided with the speaker diaphragm
10 can suppress occurrence of operation failure such as peeling of the edge portion 12 from the
vibrating portion 11, and can realize a speaker operating properly.
[0036]
The cut end face 11d for defining the outer diameter of the diaphragm portion 11 is formed by
molding the base material 20 of magnesium alloy to form the dome vibration portion 11a and
the cone vibration portion 11b of predetermined dimensions or Later, it is sufficient to punch
and cut with a mold. The step of cutting the outer diameter may be preceded by the step of
forming the oxide film layer 21, the step of forming the electrodeposition coating layer 22, and
the step of integrally forming the edge 21, respectively. It may be after. In any case, the cut end
surface 11d of the outer peripheral end 11c is covered by the roll portion 12c. The roll portion
12c connects the inner peripheral connecting portion 12a covering the outer peripheral end 11c
from the front side and the inner peripheral connecting portion 12b covering the outer
peripheral end 11c from the rear side, so the adhesion between the vibrating portion 11 and the
edge portion 12 is improves.
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12
[0037]
In the case of the present embodiment, the adhesion strength between the vibrating portion 11
and the edge 12 is 700 to 1000 gf, while the electrodeposition coating layer 22 is interposed
between the oxide film layer 21 and the edge 12. When this is done, the adhesion strength
between the vibrating portion 11 and the edge 12 decreases to 380 to 550 gf.
[0038]
The resin material constituting the edge portion 12 has a JIS-A hardness of 0 ° to 90 ° so that
the resin material penetrates and adheres to a large number of holes formed in the oxide film
layer 21 of the base material 20 containing magnesium. The thermoplastic elastomer may be any
of styrene-based thermoplastic elastomers, ethylene-based thermoplastic elastomers, ester-based
thermoplastic elastomers, and olefin-based thermoplastic elastomers.
[0039]
Further, FIG. 3 is a view for explaining an edge portion 12 of the speaker diaphragm 10.
Specifically, FIG. 3 (a) is the case of the edge 12 similar to FIGS. 1 and 2, and FIG. 3 (b) is the case
where the configuration of the inner circumferential connecting portion of the edge 12 is
different.
In the case of FIG. 3A, the inner peripheral connecting portions 12a and 12b cover the outer
peripheral end 11c of the cone vibrating portion 11b along the front side and the rear side,
respectively. On the other hand, in the case of FIG. 3B, only the inner circumference connecting
portion 12a which is a portion covering the outer circumference end 11c from the front side is
provided. In any case, the cut end face 11d which defines the outer diameter of the outer
peripheral end 11c of the cone vibrating portion 11b is covered by the roll portion 12c.
[0040]
In either case of FIG. 3A or FIG. 3B, the cross-sectional thickness T of the resin material of the
edge portion 12 is the largest at the cut end surface portion 11 d of the diaphragm portion 11,
and further, the diaphragm portion 11. The diameter decreases continuously as it goes inward in
the radial direction and as it goes outward in the radial direction of the edge portion 12. For
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example, the cross-sectional thickness T of the resin material of the edge portion 12 may be
defined as the thickness in the normal direction of the diaphragm portion 11 at the outer
peripheral end portion 11c. By continuously changing the cross-sectional thickness T of the resin
material of the edge portion 12, there is no site where the mechanical impedance changes
rapidly, and the reflection of vibration is reduced.
[0041]
FIG. 4 is a graph comparing sound pressure frequency characteristics of a speaker provided with
the speaker diaphragm 10 of the present embodiment with a comparative example. FIG. 4A
shows the case of the present embodiment shown in FIG. On the other hand, FIG. 4B is a
conventional edge in which the cross-sectional thickness T of the resin material of the edge
portion 12 does not continuously change, and defines the outer diameter of the outer peripheral
end portion 11c of the cone vibration portion 11b. This is a case of a comparative example (not
shown) in which the cut end surface 11d is not covered by the roll portion 12c.
[0042]
In the case of the present embodiment, in contrast to the comparative example, it is possible to
suppress the peak-dip of the frequency characteristic of the sound wave radiated from the
speaker diaphragm 10 and the edge portion. The divided vibration at a high frequency around
about 10 kHz can be suppressed to increase the sound pressure reproduction level. Therefore,
the speaker provided with the speaker diaphragm 10 of the present embodiment can realize
preferable reproduction sound quality.
[0043]
FIG. 5 is a view for explaining a speaker diaphragm 10a according to another preferred
embodiment of the present invention. The present embodiment is a case where the shape and
configuration of the edge portion 12 are different from those of the speaker diaphragm 10 of the
previous embodiment, and the diaphragm portion 11 having the base 20 containing a
magnesium alloy is common. Therefore, the common description and illustration are omitted.
[0044]
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14
In the speaker diaphragm 10a of the present embodiment, the edge portion 12 has an inner
diameter convex portion 12e defined by an inner diameter dimension R1 from the central axis O
defining the shape of the diaphragm and an inner diameter dimension R2 larger than the inner
diameter dimension R1. It has an annular shape in which a defined inner diameter recess 12 f
appears repeatedly in the circumferential direction. The inner diameter convex portion 12 e and
the inner diameter concave portion 12 f may be provided so as to equally divide the inner
peripheral connection portion 12 a of the annular edge portion 12 in the circumferential
direction at a predetermined angle.
[0045]
The inner diameter dimension R1 defining the inner diameter convex portion 12e is equal to the
dimension defining the inner circumferential dimension of the outer circumferential end portion
11c in the speaker diaphragm 10 of the previous embodiment. Therefore, the oxide film layer 21
is formed on the surface of the base 20 on the inner side of the inner diameter R1 of the speaker
diaphragm 10a (the part excluding the dome vibrating portion 11a and the outer peripheral end
11c of the cone-shaped cone vibrating portion 11b). An electrodeposition coating layer 22 is
further formed thereon.
[0046]
Further, only the oxide film layer 21 is formed on the surface of the base material 20 outside the
inside diameter R1 of the speaker diaphragm 10a (the outer peripheral end 11c of the coneshaped cone vibration portion 11b), and an electrodeposition coating layer 22 is not formed. An
inner diameter R2 defining the inner diameter recess 12f is an inner diameter larger than the
inner diameter R1 and smaller than an outer diameter defining the cut end face 11d of the
diaphragm portion 11. Therefore, the oxide film layer 21 of the outer peripheral end 11c of the
diaphragm portion 11 is exposed in the range of the inner diameter R1 or more corresponding to
the inner diameter recess 12e and less than the inner diameter R2.
[0047]
The edge portion 12 of the speaker diaphragm 10a is realized by a step of connecting and
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molding the edge portions 12 described below by insert molding. That is, a mold (not shown) for
holding the diaphragm portion 11 has an outer peripheral end holding portion (not shown)
holding a range in which the oxide film layer 21 is exposed at the outer peripheral end 11c. The
outer peripheral end holding portion of the mold is a convex portion that appears repeatedly in
the circumferential direction so as to correspond to the inner diameter convex portion 12 e and
the inner diameter concave portion 12 f. The outer peripheral end sandwiching portion of the
mold sandwiches the outer peripheral end 11c of the diaphragm portion 11 from both the front
side and the rear side, and therefore forms a portion to which the resin material constituting the
edge portion 12 does not flow. Therefore, the oxide film of the outer peripheral end 11 c of the
diaphragm 11 is equal to or larger than the inner diameter R1 corresponding to the inner
diameter recess 12 e formed by the outer peripheral end pinching portion of the mold and
smaller than the inner diameter R2. Layer 21 will be exposed.
[0048]
As described above, the portion where the resin material constituting the edge portion 12 does
not flow in is the portion where the outer peripheral end 11 c of the diaphragm portion 11 is
sandwiched by the outer peripheral end holding portion of the mold from both front and back
sides. Therefore, in the step of connecting and molding the edge portions 12 by insert molding,
the shape of the outer peripheral end portion 11 c of the diaphragm portion 11 can be
maintained in a predetermined shape, and resin material for forming the edge portions 12 can
flow evenly. It has the advantage of becoming When the mold does not have the outer peripheral
end holding portion, the outer peripheral end 11c of the diaphragm portion 11 can not be
pinched from both the front side and the rear side, which may cause failure to maintain a
predetermined shape. Such fear can be eliminated in the case of the embodiment. As a result,
since the speaker diaphragm 10a can be created while maintaining a predetermined diaphragm
shape, it is possible to realize a speaker that operates appropriately to exhibit predetermined
frequency characteristics.
[0049]
The oxide film layer 21 on the outer peripheral end 11c of the diaphragm portion 11 is exposed
in the range of the inner diameter dimension R1 or more corresponding to the inner diameter
recess 12e and less than the inner diameter dimension R2, but oxidation Since the film layer 21
is formed, the corrosion resistance of the magnesium diaphragm can be satisfied.
[0050]
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16
Of course, if a portion is provided in which the outer peripheral end portion 11c of the
diaphragm portion 11 is sandwiched from both the front and back sides by the outer peripheral
end holding portion of the mold, an inner diameter convex portion such as the edge portion 12
shown in FIG. It is not limited to 12e and the inner diameter recess 12f.
A plurality of pins may be provided in the mold to form an outer peripheral end holding portion,
and the outer peripheral end 11c of the diaphragm portion 11 may be held from both sides.
[0051]
The speaker using the speaker diaphragm of the present invention is also applicable to
headphones and earphones. Further, the present invention is applicable not only to home stereo
reproduction or multi-channel surround reproduction but also to in-vehicle audio equipment and
sound reproduction equipment such as movie theaters.
[0052]
10, 10a Loudspeaker diaphragm 11 diaphragm 12 edge 13 gasket 20 base 21 oxide film layer
22 electrodeposited layer
10-05-2019
17
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